K20 Body Off Rebuild

The 81 K20 in my sig is ready for a full rebuild to be ready for plowing season. It has a TBI 350 so it runs great. TH350 seems OK, NP 205 is bulletproof, and the axles are good. The frame on the truck is in very good shape, and I want to keep it that way. When I bought the truck last fall, I knew I would need to do some bodywork. I didn't realize how bad the sheet metal is, and now have a couple of donor trucks for sheet metal. There isn't much decent tin around for cabs, so I still need to rebuild the floor of the donor cab. I am going to pull all the tin off the 81. I will probably end up pulling the motor and trans/case too. I want to really clean the frame, and apply something like POR 15 to protect it long term. My goal for this summer is to preserve the frame, and have a cab that will last for many years. Probably POR 15 on the cab bottom too. I'm not going to be too fussy with the front clip, I can bolt on new inner and outer fenders anytime. I will put the best of the three beds on, eventually probably have a flatbed on it. If the funds are there I want to have the TH350 rebuilt, or have a spare on hand.

Did a little dubbing around tonight. Any suggestions getting the cab mounting bolts out? I have one that is spinning free inside the channel. It doesn't seem there is any value heating the bolt since the bushing is almost two inches thick. Should I play it safe, and cut the heads off the rest of them so I can heat the bolt and get penetrant on the threads? What about drilling a small hole in the channel and lubricating the threads that way?

Did a little dubbing around tonight. Any suggestions getting the cab mounting bolts out? I have one that is spinning free inside the channel. It doesn't seem there is any value heating the bolt since the bushing is almost two inches thick. Should I play it safe, and cut the heads off the rest of them so I can heat the bolt and get penetrant on the threads? What about drilling a small hole in the channel and lubricating the threads that way?

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First of all nice project you got going on here.

I would try to get out as many of the bolts as I can and then cut the head of any that are spinning. This will allow you to remove the cab and have a little more freedom to work on it. Hope you get it free.

I have a 84 3/4 ton i plow with and love it
i have the 4 barrell and a turbo400 tranny though:happy:

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Sadly, no. Been very busy with other stuff. I need to tear down the second donor truck. And I found a third parts truck that I am going to tear down. Then I will start on the 81. I will post some pics as soon as I get the body off.

Started tearing down the 84 tonight. That's the black one in the pics. Pulled the hood, front bumper, fenders in and out, radiator, grill, core support, doors, bed bolts, front cab mount bolts, disconnected all wiring from the motor, pulled the power steering box and pump, and a few other little things. Did this in the driveway in less than four hours after work. After I lift the bed, I need to sawzall the rear cab bolts, and that will come off. Motor and tranny and I'm done with this one. Motor is sold, Tranny is listed.

Two "mechanics" started tearing the 85 down for me earlier this year, I finished it a month or so ago. They took four hours between them. They undid the bed bolts, pulled the hood, undid the three rear bolts on the fenders, took the dash all apart (I have no idea why), pulled the radiator, and undid some wiring. It really messed me up too. The fenders took a pounding from opening and closing the doors, and getting them out around the front bumper.:grrrrrr: Oh well, live and learn.

The core support is completely stripped, ready for sandblasting. It's not perfect, but will definitely do. It's all I really wanted from the truck anyway. The doors are great, so that's a bonus.

For those of you that have done this before, is there a correct/proper procedure for the front clip? When I did the 85, I took off the front bumper last. Had a heck of time getting the fenders out. I actually scratched them up pretty good. This time I took the bumper off first. It wasn't fun, but the rest of the job seemed much easier.

Sorry there's no pics, but nothing exciting happening with this one. I should be picking up a 78 K15 this weekend. Has a TH350 which matches the 81. Probably going to rebuild one of them. It also has some Fisher Plow parts I want. Already have the 12 bolt/Dana 44 sold out of it, pays for the truck. Once the 78 is torn down, and all the scrap is hauled off, I will be tearing the 81 K25 down. There will be plenty of pics with that.

If you go with two tanks make sure the switching valve for the two tanks is good. My truck came with two tanks and I kept having a problem with it cutting off. The switching valve was bad. I wasn't completely switching between tanks. It was trying to pull off two tanks and would take on air and cut off so now I having to run off of just one tank. Just make sure you no unless you decided to by a new one which is about $350.